Litigation, Claims and Contingencies - Summary of Asbestos Claims Activity (Details) - Claim Claim in Thousands	9 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Ashland [Member]
Asbestos claims [Roll Forward]
Open claims - beginning of year	46	49	49	53	53
New claims filed	1	1	2	2	2
Claims settled	(1)	0	(1)	(1)	(1)
Claims dismissed	(1)	(3)	(4)	(5)	(1)
Open claims - end of period	45	47	46	49	53
Hercules [Member]
Asbestos claims [Roll Forward]
Open claims - beginning of year	12	12	12	13	13
New claims filed	1	1	1	1	1
Claims dismissed	(1)	(1)	(1)	(2)	(1)
Open claims - end of period	12	12	12	12	13